#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
using namespace std;

const int N = 1e6 + 10, INF = 0x3f3f3f3f;

int n, k;
int a[N], b[N];

void solve()
{
    cin >> n >> k;

    int mx = 0, mi = INF;
    for (int i = 1;i <= n;i++) {
        cin >> a[i];
        mx = max(mx, a[i]);
        mi = min(mi, a[i]);
    }

    int x = -1;
    for (int i = 1;i <= n;i++) {
        cin >> b[i];
        if (b[i] != -1) x = a[i] + b[i];
    }

    if (x != -1) {
        for (int i = 1;i <= n;i++) {
            if ((b[i] == -1 && (x - a[i] > k || x - a[i] < 0)) || (b[i] != -1 && a[i] + b[i] != x)) {
                cout << 0 << '\n'; return;
            }
        }
        cout << 1 << '\n';
    } else cout << mi + k - mx + 1 << '\n';
}

signed main()
{
    //ios::sync_with_stdio(0);
    //cin.tie(0);cout.tie(0);
#define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
    std::istringstream in(R"()");
    std::cin.rdbuf(in.rdbuf());
#endif
    int T = 1;
    cin >> T;
    for (int i = 1;i <= T;i++) {
        solve();
    }
}